"I had a Tamagotchi, but I got bored with it, and I forgot to feed it, and it died." That right there? That is the story of every single person who ever bought one of these things (or received one as a gift). I know at least four people off the top of my head who had that exact same experience. In fact, the Tamagotchi was perfectly designed for the user to get bored with it, forget to feed it, and eventually kill it.
Tamagotchi was an early experiment in making people feel bad for electronic things. This would later come to fruition in games like The Sims and Animal Crossing. One of my friends who killed her Tamagotchi also played Animal Crossing. I was over at her house one day when we decided to fire up the old console and check in on her Animal Crossing town. After thinking for a really long time, her character said "Welcome back! I haven't seen you in 1,172 days!" It was poignant as hell.
Tamagotchi and the like were marketed towards little kids. They were keychain sized, so you could snap them on your giant oversized backpack and head to school. Except that the beeping and clicking got on the nerves of teachers everywhere, and playing with your Tamagotchi was quickly banned from schools. Kids had to put their Tamagotchi into "sleep mode" or else find a babysitter for the next period. Which is an awful lot of trouble for a golf ball-sized item of personal electronics.
The graphics were terrible, even for the time. I remember looking at a friend's Tamagotchi and being confused as to what I was looking at. It was just a bunch of big dark gray pixels on a light gray background. I had a Pac Man digital watch in the 1980's which had better graphics than this thing. Was it hungry? Pooping? Holding a sandwich? Damned if I could tell.
For whatever reason, Tamagotchis became the hot thing. At least one Christmas season featured the inevitable toy store fist fights over the little plastic gizmos. Then within a few years the market was flooded with cheap knock-offs from Taiwan and China, and also everyone had already gotten bored with their first one and killed it.
What eventually doomed the Tamagotchi was that you only had enough interest for one of them. And it's not as if they ever grew up into something interesting, like a Palm Pilot.